216473661 has 16 divisors (see below), whose sum is σ = 331761600. Its totient is φ = 139338864.

The previous prime is 216473581. The next prime is 216473683. The reversal of 216473661 is 166374612.

It is a happy number.

216473661 is a `hidden beast` number, since 2 + 1 + 647 + 3 + 6 + 6 + 1 = 666.

216473661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 216473661 - 2⁹ = 216473149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216477661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 137451 + ... + 139016.

It is an arithmetic number, because the mean of its divisors is an integer number (20735100).

Almost surely, 2^216473661 is an apocalyptic number.

It is an amenable number.

216473661 is a deficient number, since it is larger than the sum of its proper divisors (115287939).

216473661 is a wasteful number, since it uses less digits than its factorization.

216473661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276505 (or 276499 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 216473661 is about 14713.0439066836. The cubic root of 216473661 is about 600.4382548099.

The spelling of 216473661 in words is "two hundred sixteen million, four hundred seventy-three thousand, six hundred sixty-one".